Hemorrhagic necrosis of the central nervous system of fetal hamsters: litter incidence and age-related pathological changes.

The occurrence, anatomic distribution, and character of lesions of spontaneous hemorrhagic necrosis (SHN) are reported in each hamster fetus of two affected litters examined on the fifteenth day of gestation and in selected individuals of other affected litters on the twelfth, thirteenth, and fourteenth days of gestation. The pathologic process seems primarily to affect the capillary vasculature of the central nervous system and shows a predilection for rapidly growing and differentiating regions of the fetal forebrain, thalamus, and brain stem. Lesions demonstrable in members of affected litters of susceptible stocks are of a progressive character, increasing both in severity and topographic extend with increasing fetal age and growth. Spontaneous patterns of regression and recurrence of SHN disease in susceptible stocks may reflect variable physiologic factors in the intrauterine environment.